Base for incandescent electric lamps



(.No Model) G. C. THOMAS. BASE Fon INCANDBSGBNT ELECTRIC LAMPS. No. 531,663.

Patented Jan'. -1, 1895 .uilllilliill o.. wAsm.

UNITED STATES PATENT OFFICE. e

GEORGEO. THOMAS, OF SOUTH FRAMINGHAM, MASSACHUSETTS.

BASEI FORiNCAN DESCENT ELECTRIC LAMPS.

v SPECIFICATION forming part of Letters Patent No. 531,663, dated January 1, 1 895.

Application tiled November 28, 1893. Serial No. 492,316. (No model.)

To a/ZZ whom it may concern:

Be it known that I, GEORGE O. THOMAS, a citizen of the United States, and a resident of South Framingham, in the county of Middlesex and State of Massachusetts, have invented certain newand useful Improvements in Bases for Incandescent Electric Lamps, of which the following is a specification.

My invention relates to the manufacture Of bases vfor incandescent electric lamps, whereby they are improved in construction and operation.

The object of my invention is to improve the base by using a vitreous intusible substance for the insulating part, and to improve the details of construction.

My invention consists in the improvements designated and combinations specifically claimed. v Y

Figure l is a side view of a base for an incandescent electric lamp. Fig. 2 is a top view. Fig. 3/is a vertical central section On line l l. Fig. eis a vertical' central section on line 2 2. Fig. 5 is a bottom view. Fig. 6 is a sectional view of the shell with the vitreous disk in place. Fig. 7 is an enlarged top view of insulating-disk and central contact piece. Fig. 8 is an enlarged sectional View on line 3 3 of Fig. 7.

A is a disk of vitreous insulating material to which are attached the contact pieces B and O.

f D is a metal shell which supports the disk A.

The contact piece B is made of some electrical conducting substance and is attached to A by means of the prongs b b forming part of B and bent so as to pass through the openings a, c, holding it firmlyin position by pressing against the inclined sides of said openings c a. One terminal of the carbon ber of the lamp consisting of a wire can be passed through either aperture a or a and soldered to B. The' contact piece O is .made of some electrical conducting substance and occupies an opening a in A. It is attached to A concentrically by means of anges c' c2 which embrace the top and bottom respectively of A and prevent their separation. The contact piece C has a recess in its surface for the purpose of receiving the wire, constituting one terminai of the carbon fiber of the lamp, which is soldered thereto. This recess may consist of agroove c4 near the edge or the edge maybe beveled as at c5, or theins ulating material may be recessed. The wire terminal may pass through-either groove a2. Y

To prevent the turning of O in A, two points c3 c3 of the flange c2 enter respectively two notches a3 asin A. The sides of opening a have the grooves a2 a2 extending from top to bottom of A. n,

To prevent a rotary movement of the disk A, with relation to the shell D, I provide the shell with an inwardly extended annular camshaped head d, and the inner surface of the disk is beveled off at opposite sides, thus Varying the thickness of the edge, or,`in other words, providing an undulating annular surface conforming to and designed to bear upon the head d.

1. In a base for an incandescent lamp, the combination of a shell having an inwardly extended cam-shaped head, and a disk of -insulating material having its edge surface col1- formed substantially to said head, substang tially as specified.

2. The combination of a shell having an inv wardly extended annular, cam shaped head, and a disk of insulating material having an undulating inner edge, substantially as specitied.

3. In bases for incandescent electric lamps, a vitreous disk having its edge of varying thickness, substantially as specified.

Signed at South Framingham, in the county of Middlesex and State of Massachusetts, this 24th day ol" November, A. D. 1893.

GEO. o. THOMAS.

M Qorrections in ,Letters ,Patent No. 531,663.`

It; is certified that in Letters Patent No. 531,663, granted January l, 1895, upon the application of' George C. Thomas,.of South Framingham, Massachusetts, for an improvement in Bases for Incandescent Electric Lamps, errors appear in theprinted specification requiring correction as follows: In lines 66, 7l, 75, 77, and 80, the Word head 7 should read bead; and that thesaid Letters Patent should be read with these corrections therein that the same may conform to the recordxof the case in the Patent O'ce. Y n l Signed, countersigned, and sealed this 29th day of January, A. D. 18955 f f Assistant S'emetm'y of the Interior. Countersigned JOHN S. SEYMOUR,

Commz'ssioher of Patents. 

